The SMAD4 transcription factor shows cytoplasmic retention in B-cells of patients with chronic lymphocytic leukemia (CLL)

  • A. S. Matvieieva
  • L. M. Kovalevska
  • E. V. Kashuba


Aim. To illuminate the reason of inactivity of the TGFB-SMAD2/3 pathways in CLL cells. Methods. CLL cells were isolated from peripheral blood of CLL patients, using gradient centrifugation at the ficoll. Expression and cellular localization of SMAD2, 3 and 4 proteins were analyzed by fluorescence microscopy, using specific antibodies. Results. The SMAD2 protein was basically not expressed in CLL cells, in contrast to B cells, isolated from the peripheral blood of a healthy donor. Moreover, the SMAD3 and SMAD4 proteins were localized exclusively in the cytoplasm (a proportion of SMAD3 was detected in the membrane) of CLL cells. Conclusions. The TGFB-SMAD2/3 signaling pathway is not active in CLL cells. We have found that SMAD2 is not expressed. Also, the nuclear heterodimers that consisted of SMAD3 and SMAD4 proteins, were not detected.

Keywords: chronic lymphocytic leukemia (CLA), acute myeloid leukemia (AML), peripheral blood B-cells, SMAD, the TGFB-SMAD2/3 signaling pathway.


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